Argon 18 Time Trial Bike Size Guide: E-118, E-119 and E-117

Argon 18 sizes its time trial and triathlon frames XS to XL, and prints a classic centimetre equivalent next to each letter. The one thing to know before anything else: Argon 18 does not publish frame stack and reach for these bikes. It publishes an armpad stack range and an armpad reach range for every size instead. That pair is the one that matters here, because it says where your elbows can sit. Browse all Argon 18 bikes at Bikeroom.

Please note. These sizes are indicative, a starting point and not a guarantee. The height bands below are Argon 18's own, from the size tool on each product page. They are wide in places and narrow in others, so read them with the armpad tables and confirm with a bike fit or our team.

Quick size finder

Find your height, cross check your leg length, then read across. The E-118 and E-119 share the same bands. Argon 18 publishes no height bands at all for the E-117, so use the armpad tables for that frame.

Trust the inseam over the height, and the armpad tables over both. Argon 18's S band spans 12 cm of rider height, the M band only 4 cm. Anyone between 164 and 180 cm should size on pad numbers rather than on the row.

How to measure yourself

Height. Stand barefoot with your back to a wall, heels together, looking straight ahead. Rest a flat object level on your head, mark the wall and measure from the floor.

Leg length (inseam). Barefoot, feet about 15 cm apart, press a book up into your crotch as if it were a saddle. Keep it level against the wall, mark the top edge and measure down to the floor.

The quick formula. Multiply your inseam in centimetres by 0.66. Match the result to Argon 18's classic equivalents: XS is 47 to 50, S is 51 to 53, M is 54 to 56, L is 57 to 59, XL is 60 to 62. An 82 cm inseam gives about 54, so M. Treat it as a cross check.

Why a time trial size is not your road size

The seat tube angle on all three frames is 78 degrees, against roughly 73 degrees on an Argon 18 road bike. That rotates you forward over the bottom bracket and takes load off the quadriceps, which is why triathletes run steep. Weight then sits on the elbows, so fit is measured as pad stack and pad reach to the centre of the armrest.

Because the pads sit well above and ahead of the head tube, the frame you need is smaller than your road frame. A rider on a 56 road bike is usually an M here, not an L. Compare with our Argon 18 road bike size guide before you assume the letter carries over.

The rules then diverge. Under UCI Article 1.3.013 the saddle tip must sit at least 5 cm behind the bottom bracket. A morphological exemption moves it forward only as far as the bottom bracket line, and you may claim it for the saddle or for the extensions, not both. Triathlon applies no such limit, so the same frame can be set up further forward for an Ironman than for a road time trial. Our guide to time trial versus triathlon bikes covers the rest of that split.

E-118 Tri+ Disc (the low and long one)

The E-118 is the UCI race frame Argon 18 built with Astana in mind, sold as a frameset in four sizes. It uses the Oneness bayonet fork and cockpit, and it is the one that gets lowest. AeroGeeks reported the launch figures in October 2019: an armrest stack 2 cm lower and a grip position 4 cm lower than the E-118 Next.

Frame stack and reach are not published. Chainstays are 413 mm and bottom bracket drop 70 mm across the range.

Fit character: the lowest front end Argon 18 offers, and the longest at its shortest setting.

E-119 Tri+ Disc (the current flagship)

The E-119 is the long course bike, with integrated storage, a deeper fork and down tube, and an XL the E-118 does not offer. Argon 18 states the Oneness cockpit comes apart with six screws on the E-119 and five on the E-118, which matters if you fly to races.

Frame stack and reach are not published. Chainstays are 413 mm and bottom bracket drop 73 mm across the range.

Fit character: taller and shorter than the E-118 at the same letter, with more storage and one more size.

E-117 Tri Disc (the widest fit window)

The E-117 is sold as a complete bike, and it is the only one of the three with Argon 18's 3D head tube. Argon 18 publishes two head tube heights per size, 0 mm and 35 mm, and the system raises the top bearing rather than stacking spacers. That extra 35 mm gives the E-117 the broadest armpad stack range here.

Fit character: the most adjustable of the three, and the easiest to grow into.

The armpad window, side by side

This is the table to size on. All figures are Argon 18's, converted from centimetres to millimetres.

Take size M. The E-118 drops to 562 mm of pad stack, 36 mm lower than the E-119, and starts 19 mm further out in reach. The E-117 sits between the two on stack with the widest window: 124 mm from lowest to highest, against 100 mm on the E-118 and 90 mm on the E-119.

What riders say about Argon 18 sizing

Two patterns come up repeatedly on the Slowtwitch forum, and the published numbers back both.

The first is that the E-118 and E-119 are not interchangeable at the same letter. In a May 2020 thread one poster warned that the E-118 sits lower and more stretched out, and that a rider on a large E-118 may be a medium E-119. The armpad tables say the same thing in millimetres.

The second is reach. In a December 2023 thread an owner of about a year called the E-119 short on reach, and a long term Argon 18 rider advised checking you can get enough of it before committing. In the 2020 thread a rider of 188 cm with an 84 cm inseam reported running an E-119 in M. It was slammed and at maximum pad reach, because an L would have been too tall. Argon 18's own band puts 188 cm in L, so that is a full size down.

A third report matters if you are near a size boundary. A rider of 175 cm with a 76 cm inseam was professionally fitted to a medium E-118 Next. Argon 18's own tool had placed him in the overlap between S and M. Our practical guide to buying a pre-owned triathlon bike covers what else to check on a second hand frameset.

Between two sizes?

Work from your fit numbers, not the letter. Find your target pad stack and pad reach, then pick the size that holds both with margin at each end rather than at the limit of its range.

Beyond that, the smaller size gives a lower and sharper position and suits a shorter torso. The larger size keeps reach in hand for a long torso and long arms. Moving from a road time trial position to long course triathlon usually calls for more pad stack, so leave room to raise the pads. One caveat from owners: the E-119 disc uses proprietary brake levers and calipers, so budget for that on a second hand bike. For these positions at professional level, see our piece on the time trial bikes of the Vuelta.

Shop Argon 18 at Bikeroom

• All Argon 18 bikes for the current road and time trial stock
• Time trial and triathlon bikes for the whole category across brands
• Pre-owned triathlon bikes if you want a complete bike that has already been ridden in

If you have your pad stack and pad reach from a fit and want to know whether an E-118 in M or an E-119 in L holds them, talk to our concierge.

Disclaimer: the size suggestions here are indicative and offered as general guidance, not a fitting guarantee. All geometry, armpad and height figures are official Argon 18 data, converted from centimetres to millimetres. They were taken from the E-118 Tri+ Disc, E-119 Tri+ Disc and E-117 Tri Disc pages on 24 September 2026. Values Argon 18 does not publish are marked as such. Always confirm against the frame you are buying, and with a professional fit.

Sources: Argon 18, E-118 Tri+ Disc, retrieved 24 September 2026; Argon 18, E-119 Tri+ Disc, retrieved 24 September 2026; Argon 18, E-117 Tri Disc, retrieved 24 September 2026; Argon 18, Tech Card E-118 Tri+ Disc; Argon 18, 3D System; Argon 18, Oneness; AeroGeeks, 8 October 2019; Slowtwitch forum, May 2020; Slowtwitch forum, December 2023.